tests: add regression tests for superblocks with bad checksums

Add regression tests to examine how e2fsck deals with random
superblock corruption such as obviously wrong fields and the checksum
itself being incorrect.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/tests/f_super_bad_csum/expect.1 b/tests/f_super_bad_csum/expect.1
new file mode 100644
index 0000000..25ced5c
--- /dev/null
+++ b/tests/f_super_bad_csum/expect.1
@@ -0,0 +1,13 @@
+ext2fs_open2: Superblock checksum does not match superblock
+../e2fsck/e2fsck: Superblock invalid, trying backup blocks...
+Pass 1: Checking inodes, blocks, and sizes
+Pass 2: Checking directory structure
+Pass 3: Checking directory connectivity
+Pass 4: Checking reference counts
+Pass 5: Checking group summary information
+Inode bitmap differences: Group 1 inode bitmap does not match checksum.
+FIXED.
+
+test_filesys: ***** FILE SYSTEM WAS MODIFIED *****
+test_filesys: 11/1024 files (0.0% non-contiguous), 1557/16384 blocks
+Exit status is 0
diff --git a/tests/f_super_bad_csum/expect.2 b/tests/f_super_bad_csum/expect.2
new file mode 100644
index 0000000..dd20919
--- /dev/null
+++ b/tests/f_super_bad_csum/expect.2
@@ -0,0 +1,7 @@
+Pass 1: Checking inodes, blocks, and sizes
+Pass 2: Checking directory structure
+Pass 3: Checking directory connectivity
+Pass 4: Checking reference counts
+Pass 5: Checking group summary information
+test_filesys: 11/1024 files (0.0% non-contiguous), 1557/16384 blocks
+Exit status is 0
diff --git a/tests/f_super_bad_csum/image.bz2 b/tests/f_super_bad_csum/image.bz2
new file mode 100644
index 0000000..cd80d4b
--- /dev/null
+++ b/tests/f_super_bad_csum/image.bz2
Binary files differ
diff --git a/tests/f_super_bad_csum/name b/tests/f_super_bad_csum/name
new file mode 100644
index 0000000..745562f
--- /dev/null
+++ b/tests/f_super_bad_csum/name
@@ -0,0 +1 @@
+bad csum in superblock (metadata_csum)
diff --git a/tests/f_super_bad_csum/script b/tests/f_super_bad_csum/script
new file mode 100755
index 0000000..cfd4189
--- /dev/null
+++ b/tests/f_super_bad_csum/script
@@ -0,0 +1,33 @@
+#!/bin/bash
+
+FSCK_OPT=-fy
+IMAGE=$test_dir/image.bz2
+
+bzip2 -d < $IMAGE > $TMPFILE
+#e2label $TMPFILE test_filesys
+
+# Run fsck to fix things?
+EXP1=$test_dir/expect.1
+OUT1=$test_name.1.log
+rm -rf $test_name.failed $test_name.ok
+
+$FSCK $FSCK_OPT $TMPFILE 2>&1 | head -n 1000 | tail -n +2 > $OUT1
+echo "Exit status is $?" >> $OUT1
+
+# Run a second time
+EXP2=$test_dir/expect.2
+OUT2=$test_name.2.log
+
+$FSCK $FSCK_OPT $TMPFILE 2>&1 | head -n 1000 | tail -n +2 > $OUT2
+echo "Exit status is $?" >> $OUT2
+
+# Figure out what happened
+if cmp -s $EXP1 $OUT1 && cmp -s $EXP2 $OUT2; then
+	echo "$test_name: $test_description: ok"
+	touch $test_name.ok
+else
+	echo "$test_name: $test_description: failed"
+	diff -u $EXP1 $OUT1 >> $test_name.failed
+	diff -u $EXP2 $OUT2 >> $test_name.failed
+fi
+unset EXP1 OUT1 EXP2 OUT2 FSCK_OPT IMAGE